ogic - manfred buchroithner - karst caves in tropical jungle: 3d mapping and generation of the...

Faculty of Environmental Sciences, Department of Geosciences, Institute for Cartography

Karst caves in tropical jungle: 3D mapping and generation of the biggest virtual cave model worldwide

Manfred F. Buchroithner & Benjamin Schröter

TU Dresden, Institute for Cartography


InDOGOlomouc 13 - 16 October 2014


Gomantong Caves – General Information

• Cave system on Borneo island,

Southeast Asia

• 30 km south of Sandakan, Malaysia

• Part of Sabah Parks Forest Reserve

• Gomantong Hill:

huge limestone formations

• Tourist attraction

• Economically important: bird’s nests

(sold as Chinese delicacy)


TU Dresden, 10.04.23 Präsentationsname XYZ Folie 13 von XYZ



Gomantong Caves - Structure

Simud Hitam= Black cave

Simud Putih= White cave

Major entrance

32

2 m

ete

rs

330 meters

• Main entrance• Ceiling up to

90 m high• Parly open to

public• Walkway

• Entrance 90 m above Black cave

• Not open to public

• Still not fully explored


Laserscanning of the Cave System

• Equipment:

• 2012: Faro Focus 3D S 120

2014: Faro Focus 3D X330

• 244000 points/second

• 121 scans performed

• 5.3 billion points totally

• 21 gigabytes raw data

• 8500 scanner-taken colour photos

all only in 2012; 2014 even more

• GPS reference points to combine

with aerial imagery


Using UAV to Discover Gomantong Hill

• Need for high-resolution imagery instead existing 30 m resolution ASTER

dataset

• Equipment: Trimble Gatewing X100 autonomous drone

• Wingspan of 100 cm, easy to transport

• Flying at 400 m elevation

• 240 overlapping images with ~ 6 cm geometric resolution

• Covering complete Gomantong Hill: approx. 2.1 km2

• GPS control points taken using a Trimble GeoXH 600 and Trimble NetR9 base

station


TU Dresden, 10.04.23 Präsentationsname XYZ Folie 50 von XYZThe Gatewing X100 drone


Data Processing and Video Creation

TLS pointcloudsRegistration of pointclouds

Creation of 3D vrml terrain

Meshing a 3D geometry

Texturing

Aerial raw dataReferencing and mosaicing a DSM

Render video

FARO SCENE Geomagic Studio

MeshLab

Gatewing Stretchout

VTBuilder CINEMA 4D


TLS Data Processing – Point Cloud Registration

• 121 single scanfiles need to know their position among each other

• Registration with FARO SCENE using reference spheres placed in the caves

• Colorization, subsampling, export as .vrml file

Raw pointcloud After applying image textures


TLS Data Processing – Meshing and Texturing

Meshing: Geomagic Studio

• Preprocessing: noise reduction, outlier removal

• 121 million points polygons

• Cleaning, filling holes

Texturing: MeshLab

• Geometry + better resolved pointcloud model with *.jpg texture ready for

3D studio



Part of the 3D cave model, including separately modeled walkway


Aerial Data Processing

• Software: Gatewing Stretchout

• Converts X100 image data to accurate orthophotos and DSMs

• Dataset contains 240 original images, 227 were used

• Georeferencing with 6 Ground Control Points (GCP) geotiff

• Converting into vrml 3D geometry using free VTBuilder + Geomagic Studio

Ortho Mosaic Digital Surface Model (DSM)


TU Dresden, 10.04.23 Präsentationsname XYZ Folie 56 von XYZExported 3D geometry (*.wrl ready to use in every 3D studio)



• Scientific analyses (speleologic, geologic, hydrologic, volume estimation…)

• Nest-bat counting algorithm automated procedure

• Visualization: Video

TLS & UAV data combined

(8550 frames, 5:42 min)

Application of 3D Model


National Geographic: Gomantong 2012(Guy van Rentergem)


Virtual Flight – Gomantong(Stefan Hautz)


Thank you for your attention!

Manfred F. Buchroithner & Benjamin Schröter

[email protected]

InDOGOlomouc 13 - 16 October 2014

ogic - manfred buchroithner - karst caves in tropical jungle: 3d mapping and generation of the...

Data & Analytics

department of geosciences

cartography keith christenson

cartography cave system

prsentationsname xyz

cartographytu dresden

karst caves

black cavesimud putih

cartographysimud hitam